The role of psychiatric evaluation and testimony on 202 cases demonstrates the participation of mental health experts in the legal process. The majority of these cases fall outside the mental abnormal groupings of 'incompetent to stand trial' or 'criminal insane'. A finding of diminished responsibility on account of mental illness provides for a finding of extenuating circumstances on account of mental illness. The numerous factors and categories influencing the defendant's behaviour are specific to each, requiring presentation for the court's discretion as to significance of psychiatric factors in extenuation of sentence. The population studies as representative of psychiatric extenuation are a personal consecutive sample of court referrals for formal evaluation undertaken in a psychiatric hospital unit. Reasons for referral all include possible psychiatric disorder. One third of referrals were accused of killing a family member. Alcohol and drugs were contributory to the behaviour in 50 per cent of cases. The contributions of witchcraft and history of head injury to the sample are evident in subgroupings. The value of psychiatric contribution to the courts is discussed in relation to South African legal process and clinical experiences.